The nonlinear polarizations which lead to mode‐locking in solid‐state lasers are examined under the realistic assumption that many modes oscillate. When all possible contributions to these polarizations are included in an estimate of their strength, it is found that self‐locking is to be expected in pulsed ruby and Nd‐glass lasers, and in Q‐switched ruby, Nd‐glass, and Nd&sngbnd;YAG lasers. In particular, we find that the strengths of the various locking terms increase with the total energy in all the oscillating modes and also with decreasing mode spacing. The total number of modes into which the energy is distributed influences the locking range weakly through a term logarithmic in this number. Experimental evidence in support of these conclusions is also presented.